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19 articles for “CDMA”
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Research ArticleOpen accessIn the keywordsEfficient Detection Algorithm for a Multiple-Input and Multiple-Output Multiuser Multi-Carrier Code Division Multiple Access in Time-Varying ChannelsFares Sayadi, Mahamod Ismail, Norbahiah Misran et al.Problem statement: Maximum Likelihood (ML) decoding has been applied for the uplink of a Multi-Carrier Code Division Multiple Access (MC-CDMA) system based on Orthogonal Frequency Division Multiplexing (OFDM). Multiple-Input Multiple-Output (MIMO) channel from k users, which moves at vehicular speed, to the Base-Station (BS) is time-varying. For time-varying channels, Sphere Decoding (SD) was introduced to perform ML decoding. Whereas, computational … …American Journal of Engineering and Applied Sciences, Vol. 2, Issue 4 · 31 Dec 2009 · 7,576 accessesView PDFCite
Research ArticleOpen accessIn the keywordsSolving the Near-Far Problem in Dynamic Frequency Hopping-Optical Code Division Multiple Access using Power ControlW. J.M. Al-galbi, M. Mokhtar, A. F. Abas et al.Problem statement: In this study, a distributed power control algorithm is proposed for Dynamic Frequency Hopping Optical-CDMA (DFH-OCDMA) system. Approach: In general, the DFH-OCDMA can support higher number of simultaneous users compared to other OCDMA techniques. However, the performance of such system degrades significantly as the received power does lower than its minimum threshold. Results: This may obviously occur in … …Journal of Computer Science, Vol. 5, Issue 6 · 30 Jun 2009 · 7,521 accessesView PDFCite
Research ArticleOpen accessIn the keywordsImplementation of a Novel Concatenated FEC by RS and Irregular Turbo Codes on OFDM SystemsA. Shanmugam, A. R. Abdul Rajak, S. Vishwanath, R. UpendraCode Division Multiple Access (CDMA) performs well in a multi-cellular environment where a single frequency is used in all cells. Code Division Multiple Access (CDMA) has severe problems associated with multipath and Channel news. One possible problem is that the receiver may require a very large dynamic range in order to handle the large signal strength variation among users. Due … …American Journal of Applied Sciences, Vol. 2, Issue 5 · 31 May 2005 · 7,039 accessesView PDFCite
Review ArticleOpen accessIn the keywordsA Review on Cognitive Radio for Next Generation Cellular Network and its ChallengesNandhakumar Pandi, Arun KumarCognitive Radio (CR) is considered an intelligent technology. It improves the utilization of the radio spectrum. The increasing number of new devices has resulted in growing congestion of the ISM bands. FCC issued an order only permitting unlicensed users (secondary users) to operate in white space without interfering with licensed users (primary users). Cognitive Radio Networks (CRNs) provides a solution … …American Journal of Engineering and Applied Sciences, Vol. 10, Issue 2 · 4 Apr 2017 · 8,986 accessesView PDFCite
Research ArticleOpen accessIn the keywordsKey Success Factors of 3rd Generation Mobile Network Services for M-Commerce in MalaysiaSaravanan MuthaiyahWhile there has been a great deal of excitement in view of M-commerce, very little is actually known about conditions and critical success factors for successful introduction of the 3rd generation mobile network services here in Malaysia. This study investigates the factors for successful diffusion of 3G network services and their role in advancing an interactive marketplace. 3G which simply … …American Journal of Applied Sciences, Vol. 1, Issue 4 · 31 Dec 2004 · 6,876 accessesView PDFCite
Research ArticleOpen accessIn the abstractIMPROVING THE PERFORMANCE AND REDUCING BIT ERROR RATE ON WIRELESS DEEP FADING ENVIRONMENT RECEIVERSK. Jayanthi, V. P. Arunachalam, C. VasanthanayakiOne of the major challenges in wireless communication system is increasing complexity and reducing performance in detecting the received digital information in indoor and outdoor Environments. Consequently to overcome this problem we analyze the delay performance of a multiuser with perfect channel state information transmitting data on deep fading environment. In this proposed system, the Wireless Deep Fading Environment (WDFE) … …Journal of Computer Science, Vol. 10, Issue 3 · 29 Nov 2013 · 7,100 accessesView PDFCite
Research ArticleOpen accessIn the abstractOptical Code-Division Multiple-Access and Wavelength Division Multiplexing: Hybrid Scheme ReviewHesham A. Bakarman, P. Susthitha Menon, Isaac A.M. Ashour, Sahbudin ShaariProblem statement: Hybrid Optical Code-Division Multiple-Access (OCDMA) and Wavelength-Division Multiplexing (WDM) have flourished as successful schemes for expanding the transmission capacity as well as enhancing the security for OCDMA. However, a comprehensive review related to this hybrid system are lacking currently. Approach: The purpose of this paper is to review the literature on OCDMA-WDM overlay systems, including our hybrid approach … …Journal of Computer Science, Vol. 8, Issue 10 · 29 Aug 2012 · 7,859 accessesView PDFCite
Research ArticleOpen accessIn the abstractMultiple Input Multiple Output System with Space Time Block Coding and Orthogonal Frequency Division MultiplexingP. Ramesh Kumar, R. M.S. ParvathiProblem statement: A large amount of research has been performed to achieve very high data rate networks to support reliable transmission of video, data and speech at high rates to many users. One way to increase the data rate in a wireless system is to use multiple transmit and/or receive antennas (MIMO structure). Indeed, it has been shown that the … …Journal of Computer Science, Vol. 8, Issue 4 · 26 Jan 2012 · 6,759 accessesView PDFCite
Research ArticleOpen accessIn the abstractPerformance Evaluation of Multi-Pulse Based Code Excited Linear Predictive Speech Coder with Bitrate Scalable Tool over Additive White Gaussian Noise and Rayleigh Fading ChannelsSuphattharachai ChomphanProblem statement: In the modern speech communication technology, the speech coding with bitrate scalability was needed. However, various types of noises in the communication channels cause damages in the transmitted information especially speech data. Tonal-language speech was also affected by this situation. Approach: Based on the high pitch delay resolution technique, the MPCELP speech coding was proposed over the environment … …Journal of Computer Science, Vol. 6, Issue 12 · 6 Nov 2010 · 7,085 accessesView PDFCite